This invention relates to the field of magnetic holders. More particularly the invention relates to magnetic holders utilizing a permanent magnet having high magnetic holding force but is easily removed from the work surface.
In the area of ship maintenance it is necessary to provide a way for personnel to service hulls. Large ships, such as ocean going vessels have hulls that curve in below the deck line so that it is not possible to reach the hull when lowered down from the deck on devices such as platforms. When using platforms to lower personnel and equipment it is necessary to pull them to the hull so that the hull can be reached.
Heretofore, ships have been provided with hooks welded onto their hulls. Personnel servicing the hull tie onto and off from these hooks with ropes thereby enabling them to pull themselves to the surface and move about to various locations on the hull. Depending on the size of ship, hundreds of these hooks are required. These hooks are subject to corrosion and must be served by painting and rewelding just as the hull is serviced. Additionally, it is time consuming and not an easy task to tie onto and off from these hooks.
Another means for allowing personnel to move about over the surface of the hull includes plunger like devices that create a vacuum between the surface and plunger to hold the device and personnel. These devices are not always effective due to surface irregularities and corrosion that prevent the necessary seal between the surface and plunger material. Also, it is difficult for personnel to hold the plunger and perform the servicing functions at the same time. These devices can and do develop high holding force when a good seal is obtained and can be difficult to remove without prying and twisting.
It can be appreciated that it is highly desirable to have a means for allowing personnel to pull themselves to the surface of the hull of a ship and for allowing them to move about over the surface with minimum effort.